/***************************************************************************/
/*                                                                         */
/*  aflatin.c                                                              */
/*                                                                         */
/*    Auto-fitter hinting routines for latin script (body).                */
/*                                                                         */
/*  Copyright 2003-2012 by                                                 */
/*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
/*                                                                         */
/*  This file is part of the FreeType project, and may only be used,       */
/*  modified, and distributed under the terms of the FreeType project      */
/*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
/*  this file you indicate that you have read the license and              */
/*  understand and accept it fully.                                        */
/*                                                                         */
/***************************************************************************/


#include <ft2build.h>
#include FT_ADVANCES_H
#include FT_INTERNAL_DEBUG_H

#include "aflatin.h"
#include "aferrors.h"


#ifdef AF_CONFIG_OPTION_USE_WARPER
#include "afwarp.h"
#endif


/*************************************************************************/
/*                                                                       */
/* The macro FT_COMPONENT is used in trace mode.  It is an implicit      */
/* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log  */
/* messages during execution.                                            */
/*                                                                       */
#undef  FT_COMPONENT
#define FT_COMPONENT  trace_aflatin


/*************************************************************************/
/*************************************************************************/
/*****                                                               *****/
/*****            L A T I N   G L O B A L   M E T R I C S            *****/
/*****                                                               *****/
/*************************************************************************/
/*************************************************************************/


/* Find segments and links, compute all stem widths, and initialize */
/* standard width and height for the glyph with given charcode.     */

FT_LOCAL_DEF( void )
af_latin_metrics_init_widths( AF_LatinMetrics metrics,
                              FT_Face face,
                              FT_ULong charcode )
{
    /* scan the array of segments in each direction */
    AF_GlyphHintsRec hints[1];


    af_glyph_hints_init( hints, face->memory );

    metrics->axis[ AF_DIMENSION_HORZ ].width_count = 0;
    metrics->axis[ AF_DIMENSION_VERT ].width_count = 0;

    {
        FT_Error error;
        FT_UInt glyph_index;
        int dim;
        AF_LatinMetricsRec dummy[1];
        AF_Scaler scaler = &dummy->root.scaler;


        glyph_index = FT_Get_Char_Index( face, charcode );
        if ( glyph_index == 0 )
        {
            goto Exit;
        }

        error = FT_Load_Glyph( face, glyph_index, FT_LOAD_NO_SCALE);
        if ( error || face->glyph->outline.n_points <= 0 )
        {
            goto Exit;
        }

        FT_ZERO( dummy );

        dummy->units_per_em = metrics->units_per_em;

        scaler->x_scale = 0x10000L;
        scaler->y_scale = 0x10000L;
        scaler->x_delta = 0;
        scaler->y_delta = 0;

        scaler->face = face;
        scaler->render_mode = FT_RENDER_MODE_NORMAL;
        scaler->flags = 0;

        af_glyph_hints_rescale( hints, ( AF_ScriptMetrics ) dummy );

        error = af_glyph_hints_reload( hints, &face->glyph->outline );
        if ( error )
        {
            goto Exit;
        }

        for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ )
        {
            AF_LatinAxis axis = &metrics->axis[ dim ];
            AF_AxisHints axhints = &hints->axis[ dim ];
            AF_Segment seg, limit, link;
            FT_UInt num_widths = 0;


            error = af_latin_hints_compute_segments( hints,
                                                     ( AF_Dimension ) dim );
            if ( error )
            {
                goto Exit;
            }

            af_latin_hints_link_segments( hints,
                                          ( AF_Dimension ) dim );

            seg = axhints->segments;
            limit = seg + axhints->num_segments;

            for ( ; seg < limit; seg++ )
            {
                link = seg->link;

                /* we only consider stem segments there! */
                if ( link && link->link == seg && link > seg )
                {
                    FT_Pos dist;


                    dist = seg->pos - link->pos;
                    if ( dist < 0 )
                    {
                        dist = -dist;
                    }

                    if ( num_widths < AF_LATIN_MAX_WIDTHS )
                    {
                        axis->widths[ num_widths++ ].org = dist;
                    }
                }
            }

            af_sort_widths( num_widths, axis->widths );
            axis->width_count = num_widths;
        }

        Exit:
        for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ )
        {
            AF_LatinAxis axis = &metrics->axis[ dim ];
            FT_Pos stdw;


            stdw = ( axis->width_count > 0 )
                   ? axis->widths[ 0 ].org
                   : AF_LATIN_CONSTANT( metrics, 50 );

            /* let's try 20% of the smallest width */
            axis->edge_distance_threshold = stdw / 5;
            axis->standard_width = stdw;
            axis->extra_light = 0;
        }
    }

    af_glyph_hints_done( hints );
}


#define AF_LATIN_MAX_TEST_CHARACTERS  12


static const char af_latin_blue_chars[AF_LATIN_MAX_BLUES]
[AF_LATIN_MAX_TEST_CHARACTERS + 1] =
        {
                "THEZOCQS",
                "HEZLOCUS",
                "fijkdbh",
                "xzroesc",
                "xzroesc",
                "pqgjy"
        };


/* Find all blue zones.  Flat segments give the reference points, */
/* round segments the overshoot positions.                        */

static void
af_latin_metrics_init_blues( AF_LatinMetrics metrics,
                             FT_Face face )
{
    FT_Pos flats[AF_LATIN_MAX_TEST_CHARACTERS];
    FT_Pos rounds[AF_LATIN_MAX_TEST_CHARACTERS];
    FT_Int num_flats;
    FT_Int num_rounds;
    FT_Int bb;
    AF_LatinBlue blue;
    FT_Error error;
    AF_LatinAxis axis = &metrics->axis[ AF_DIMENSION_VERT ];
    FT_GlyphSlot glyph = face->glyph;


    /* we compute the blues simply by loading each character from the    */
    /* `af_latin_blue_chars[blues]' string, then finding its top-most or */
    /* bottom-most points (depending on `AF_IS_TOP_BLUE')                */

    FT_TRACE5(( "blue zones computation\n" ));
    FT_TRACE5(( "------------------------------------------------\n" ));

    for ( bb = 0; bb < AF_LATIN_BLUE_MAX; bb++ )
    {
        const char *p = af_latin_blue_chars[ bb ];
        const char *limit = p + AF_LATIN_MAX_TEST_CHARACTERS;
        FT_Pos *blue_ref;
        FT_Pos *blue_shoot;


        FT_TRACE5(( "blue %3d: ", bb ));

        num_flats = 0;
        num_rounds = 0;

        for ( ; p < limit && *p; p++ )
        {
            FT_UInt glyph_index;
            FT_Pos best_y;                            /* same as points.y */
            FT_Int best_point, best_first, best_last;
            FT_Vector *points;
            FT_Bool round = 0;


            FT_TRACE5(( "'%c'", *p ));

            /* load the character in the face -- skip unknown or empty ones */
            glyph_index = FT_Get_Char_Index( face, ( FT_UInt ) *p );
            if ( glyph_index == 0 )
            {
                continue;
            }

            error = FT_Load_Glyph( face, glyph_index, FT_LOAD_NO_SCALE);
            if ( error || glyph->outline.n_points <= 0 )
            {
                continue;
            }

            /* now compute min or max point indices and coordinates */
            points = glyph->outline.points;
            best_point = -1;
            best_y = 0;  /* make compiler happy */
            best_first = 0;  /* ditto */
            best_last = 0;  /* ditto */

            {
                FT_Int nn;
                FT_Int first = 0;
                FT_Int last = -1;


                for ( nn = 0;
                      nn < glyph->outline.n_contours;
                      first = last + 1, nn++ )
                {
                    FT_Int old_best_point = best_point;
                    FT_Int pp;


                    last = glyph->outline.contours[ nn ];

                    /* Avoid single-point contours since they are never rasterized. */
                    /* In some fonts, they correspond to mark attachment points     */
                    /* which are way outside of the glyph's real outline.           */
                    if ( last <= first )
                    {
                        continue;
                    }

                    if ( AF_LATIN_IS_TOP_BLUE( bb ))
                    {
                        for ( pp = first; pp <= last; pp++ )
                        {
                            if ( best_point < 0 || points[ pp ].y > best_y )
                            {
                                best_point = pp;
                                best_y = points[ pp ].y;
                            }
                        }
                    }
                    else
                    {
                        for ( pp = first; pp <= last; pp++ )
                        {
                            if ( best_point < 0 || points[ pp ].y < best_y )
                            {
                                best_point = pp;
                                best_y = points[ pp ].y;
                            }
                        }
                    }

                    if ( best_point != old_best_point )
                    {
                        best_first = first;
                        best_last = last;
                    }
                }
                FT_TRACE5(( "%5d", best_y ));
            }

            /* now check whether the point belongs to a straight or round   */
            /* segment; we first need to find in which contour the extremum */
            /* lies, then inspect its previous and next points              */
            if ( best_point >= 0 )
            {
                FT_Int prev, next;
                FT_Pos dist;


                /* now look for the previous and next points that are not on the */
                /* same Y coordinate.  Threshold the `closeness'...              */
                prev = best_point;
                next = prev;

                do
                {
                    if ( prev > best_first )
                    {
                        prev--;
                    }
                    else
                    {
                        prev = best_last;
                    }

                    dist = points[ prev ].y - best_y;
                    if ( dist < -5 || dist > 5 )
                    {
                        break;
                    }

                }
                while ( prev != best_point );

                do
                {
                    if ( next < best_last )
                    {
                        next++;
                    }
                    else
                    {
                        next = best_first;
                    }

                    dist = points[ next ].y - best_y;
                    if ( dist < -5 || dist > 5 )
                    {
                        break;
                    }

                }
                while ( next != best_point );

                /* now set the `round' flag depending on the segment's kind */
                round = FT_BOOL(
                        FT_CURVE_TAG( glyph->outline.tags[ prev ] ) != FT_CURVE_TAG_ON ||
                        FT_CURVE_TAG( glyph->outline.tags[ next ] ) != FT_CURVE_TAG_ON );

                FT_TRACE5(( "%c ", round ? 'r' : 'f' ));
            }

            if ( round )
            {
                rounds[ num_rounds++ ] = best_y;
            }
            else
            {
                flats[ num_flats++ ] = best_y;
            }
        }

        FT_TRACE5(( "\n" ));

        if ( num_flats == 0 && num_rounds == 0 )
        {
            /*
             *  we couldn't find a single glyph to compute this blue zone,
             *  we will simply ignore it then
             */
            FT_TRACE5(( "empty\n" ));
            continue;
        }

        /* we have computed the contents of the `rounds' and `flats' tables, */
        /* now determine the reference and overshoot position of the blue -- */
        /* we simply take the median value after a simple sort               */
        af_sort_pos( num_rounds, rounds );
        af_sort_pos( num_flats, flats );

        blue = &axis->blues[ axis->blue_count ];
        blue_ref = &blue->ref.org;
        blue_shoot = &blue->shoot.org;

        axis->blue_count++;

        if ( num_flats == 0 )
        {
            *blue_ref =
            *blue_shoot = rounds[ num_rounds / 2 ];
        }
        else if ( num_rounds == 0 )
        {
            *blue_ref =
            *blue_shoot = flats[ num_flats / 2 ];
        }
        else
        {
            *blue_ref = flats[ num_flats / 2 ];
            *blue_shoot = rounds[ num_rounds / 2 ];
        }

        /* there are sometimes problems: if the overshoot position of top     */
        /* zones is under its reference position, or the opposite for bottom  */
        /* zones.  We must thus check everything there and correct the errors */
        if ( *blue_shoot != *blue_ref )
        {
            FT_Pos ref = *blue_ref;
            FT_Pos shoot = *blue_shoot;
            FT_Bool over_ref = FT_BOOL( shoot > ref );


            if ( AF_LATIN_IS_TOP_BLUE( bb ) ^ over_ref )
            {
                *blue_ref =
                *blue_shoot = ( shoot + ref ) / 2;
            }
        }

        blue->flags = 0;
        if ( AF_LATIN_IS_TOP_BLUE( bb ))
        {
            blue->flags |= AF_LATIN_BLUE_TOP;
        }

        /*
         * The following flag is used later to adjust the y and x scales
         * in order to optimize the pixel grid alignment of the top of small
         * letters.
         */
        if ( bb == AF_LATIN_BLUE_SMALL_TOP )
        {
            blue->flags |= AF_LATIN_BLUE_ADJUSTMENT;
        }

        FT_TRACE5(( "-- ref = %ld, shoot = %ld\n", *blue_ref, *blue_shoot ));
    }

    FT_TRACE5(( "\n" ));

    return;
}


/* Check whether all ASCII digits have the same advance width. */

FT_LOCAL_DEF( void )
af_latin_metrics_check_digits( AF_LatinMetrics metrics,
                               FT_Face face )
{
    FT_UInt i;
    FT_Bool started = 0, same_width = 1;
    FT_Fixed advance, old_advance = 0;


    /* digit `0' is 0x30 in all supported charmaps */
    for ( i = 0x30; i <= 0x39; i++ )
    {
        FT_UInt glyph_index;


        glyph_index = FT_Get_Char_Index( face, i );
        if ( glyph_index == 0 )
        {
            continue;
        }

        if ( FT_Get_Advance( face, glyph_index,
                             FT_LOAD_NO_SCALE |
                             FT_LOAD_NO_HINTING |
                             FT_LOAD_IGNORE_TRANSFORM,
                             &advance ))
        {
            continue;
        }

        if ( started )
        {
            if ( advance != old_advance )
            {
                same_width = 0;
                break;
            }
        }
        else
        {
            old_advance = advance;
            started = 1;
        }
    }

    metrics->root.digits_have_same_width = same_width;
}


/* Initialize global metrics. */

FT_LOCAL_DEF( FT_Error )
af_latin_metrics_init( AF_LatinMetrics metrics,
                       FT_Face face )
{
    FT_Error error = AF_Err_Ok;
    FT_CharMap oldmap = face->charmap;
    FT_UInt ee;

    static const FT_Encoding latin_encodings[] =
            {
                    FT_ENCODING_UNICODE,
                    FT_ENCODING_APPLE_ROMAN,
                    FT_ENCODING_ADOBE_STANDARD,
                    FT_ENCODING_ADOBE_LATIN_1,

                    FT_ENCODING_NONE  /* end of list */
            };


    metrics->units_per_em = face->units_per_EM;

    /* do we have a latin charmap in there? */
    for ( ee = 0; latin_encodings[ ee ] != FT_ENCODING_NONE; ee++ )
    {
        error = FT_Select_Charmap( face, latin_encodings[ ee ] );
        if ( !error )
        {
            break;
        }
    }

    if ( !error )
    {
        /* For now, compute the standard width and height from the `o'. */
        af_latin_metrics_init_widths( metrics, face, 'o' );
        af_latin_metrics_init_blues( metrics, face );
        af_latin_metrics_check_digits( metrics, face );
    }

    FT_Set_Charmap( face, oldmap );
    return AF_Err_Ok;
}


/* Adjust scaling value, then scale and shift widths   */
/* and blue zones (if applicable) for given dimension. */

static void
af_latin_metrics_scale_dim( AF_LatinMetrics metrics,
                            AF_Scaler scaler,
                            AF_Dimension dim )
{
    FT_Fixed scale;
    FT_Pos delta;
    AF_LatinAxis axis;
    FT_UInt nn;


    if ( dim == AF_DIMENSION_HORZ )
    {
        scale = scaler->x_scale;
        delta = scaler->x_delta;
    }
    else
    {
        scale = scaler->y_scale;
        delta = scaler->y_delta;
    }

    axis = &metrics->axis[ dim ];

    if ( axis->org_scale == scale && axis->org_delta == delta )
    {
        return;
    }

    axis->org_scale = scale;
    axis->org_delta = delta;

    /*
     * correct X and Y scale to optimize the alignment of the top of small
     * letters to the pixel grid
     */
    {
        AF_LatinAxis Axis = &metrics->axis[ AF_DIMENSION_VERT ];
        AF_LatinBlue blue = NULL;


        for ( nn = 0; nn < Axis->blue_count; nn++ )
        {
            if ( Axis->blues[ nn ].flags & AF_LATIN_BLUE_ADJUSTMENT )
            {
                blue = &Axis->blues[ nn ];
                break;
            }
        }

        if ( blue )
        {
            FT_Pos scaled = FT_MulFix( blue->shoot.org, scaler->y_scale );
            FT_Pos fitted = ( scaled + 40 ) & ~63;


            if ( scaled != fitted )
            {
#if 0
                if ( dim == AF_DIMENSION_HORZ )
                {
                  if ( fitted < scaled )
                    scale -= scale / 50;  /* scale *= 0.98 */
                }
                else
#endif
                if ( dim == AF_DIMENSION_VERT )
                {
                    scale = FT_MulDiv( scale, fitted, scaled );
                }
            }
        }
    }

    axis->scale = scale;
    axis->delta = delta;

    if ( dim == AF_DIMENSION_HORZ )
    {
        metrics->root.scaler.x_scale = scale;
        metrics->root.scaler.x_delta = delta;
    }
    else
    {
        metrics->root.scaler.y_scale = scale;
        metrics->root.scaler.y_delta = delta;
    }

    /* scale the widths */
    for ( nn = 0; nn < axis->width_count; nn++ )
    {
        AF_Width width = axis->widths + nn;


        width->cur = FT_MulFix( width->org, scale );
        width->fit = width->cur;
    }

    /* an extra-light axis corresponds to a standard width that is */
    /* smaller than 5/8 pixels                                     */
    axis->extra_light =
            ( FT_Bool ) ( FT_MulFix( axis->standard_width, scale ) < 32 + 8 );

    if ( dim == AF_DIMENSION_VERT )
    {
        /* scale the blue zones */
        for ( nn = 0; nn < axis->blue_count; nn++ )
        {
            AF_LatinBlue blue = &axis->blues[ nn ];
            FT_Pos dist;


            blue->ref.cur = FT_MulFix( blue->ref.org, scale ) + delta;
            blue->ref.fit = blue->ref.cur;
            blue->shoot.cur = FT_MulFix( blue->shoot.org, scale ) + delta;
            blue->shoot.fit = blue->shoot.cur;
            blue->flags &= ~AF_LATIN_BLUE_ACTIVE;

            /* a blue zone is only active if it is less than 3/4 pixels tall */
            dist = FT_MulFix( blue->ref.org - blue->shoot.org, scale );
            if ( dist <= 48 && dist >= -48 )
            {
#if 0
                FT_Pos  delta1;
#endif
                FT_Pos delta2;


                /* use discrete values for blue zone widths */

#if 0

                /* generic, original code */
                delta1 = blue->shoot.org - blue->ref.org;
                delta2 = delta1;
                if ( delta1 < 0 )
                  delta2 = -delta2;

                delta2 = FT_MulFix( delta2, scale );

                if ( delta2 < 32 )
                  delta2 = 0;
                else if ( delta2 < 64 )
                  delta2 = 32 + ( ( ( delta2 - 32 ) + 16 ) & ~31 );
                else
                  delta2 = FT_PIX_ROUND( delta2 );

                if ( delta1 < 0 )
                  delta2 = -delta2;

                blue->ref.fit   = FT_PIX_ROUND( blue->ref.cur );
                blue->shoot.fit = blue->ref.fit + delta2;

#else

                /* simplified version due to abs(dist) <= 48 */
                delta2 = dist;
                if ( dist < 0 )
                {
                    delta2 = -delta2;
                }

                if ( delta2 < 32 )
                {
                    delta2 = 0;
                }
                else if ( delta < 48 )
                {
                    delta2 = 32;
                }
                else
                {
                    delta2 = 64;
                }

                if ( dist < 0 )
                {
                    delta2 = -delta2;
                }

                blue->ref.fit = FT_PIX_ROUND( blue->ref.cur );
                blue->shoot.fit = blue->ref.fit - delta2;

#endif

                blue->flags |= AF_LATIN_BLUE_ACTIVE;
            }
        }
    }
}


/* Scale global values in both directions. */

FT_LOCAL_DEF( void )
af_latin_metrics_scale( AF_LatinMetrics metrics,
                        AF_Scaler scaler )
{
    metrics->root.scaler.render_mode = scaler->render_mode;
    metrics->root.scaler.face = scaler->face;
    metrics->root.scaler.flags = scaler->flags;

    af_latin_metrics_scale_dim( metrics, scaler, AF_DIMENSION_HORZ );
    af_latin_metrics_scale_dim( metrics, scaler, AF_DIMENSION_VERT );
}


/*************************************************************************/
/*************************************************************************/
/*****                                                               *****/
/*****           L A T I N   G L Y P H   A N A L Y S I S             *****/
/*****                                                               *****/
/*************************************************************************/
/*************************************************************************/


/* Walk over all contours and compute its segments. */

FT_LOCAL_DEF( FT_Error )
af_latin_hints_compute_segments( AF_GlyphHints hints,
                                 AF_Dimension dim )
{
    AF_AxisHints axis = &hints->axis[ dim ];
    FT_Memory memory = hints->memory;
    FT_Error error = AF_Err_Ok;
    AF_Segment segment = NULL;
    AF_SegmentRec seg0;
    AF_Point *contour = hints->contours;
    AF_Point *contour_limit = contour + hints->num_contours;
    AF_Direction major_dir, segment_dir;


    FT_ZERO( &seg0 );
    seg0.score = 32000;
    seg0.flags = AF_EDGE_NORMAL;

    major_dir = ( AF_Direction ) FT_ABS( axis->major_dir );
    segment_dir = major_dir;

    axis->num_segments = 0;

    /* set up (u,v) in each point */
    if ( dim == AF_DIMENSION_HORZ )
    {
        AF_Point point = hints->points;
        AF_Point limit = point + hints->num_points;


        for ( ; point < limit; point++ )
        {
            point->u = point->fx;
            point->v = point->fy;
        }
    }
    else
    {
        AF_Point point = hints->points;
        AF_Point limit = point + hints->num_points;


        for ( ; point < limit; point++ )
        {
            point->u = point->fy;
            point->v = point->fx;
        }
    }

    /* do each contour separately */
    for ( ; contour < contour_limit; contour++ )
    {
        AF_Point point = contour[ 0 ];
        AF_Point last = point->prev;
        int on_edge = 0;
        FT_Pos min_pos = 32000;  /* minimum segment pos != min_coord */
        FT_Pos max_pos = -32000;  /* maximum segment pos != max_coord */
        FT_Bool passed;


        if ( point == last )
        {  /* skip singletons -- just in case */
            continue;
        }

        if ( FT_ABS( last->out_dir ) == major_dir &&
             FT_ABS( point->out_dir ) == major_dir )
        {
            /* we are already on an edge, try to locate its start */
            last = point;

            for ( ;; )
            {
                point = point->prev;
                if ( FT_ABS( point->out_dir ) != major_dir )
                {
                    point = point->next;
                    break;
                }
                if ( point == last )
                {
                    break;
                }
            }
        }

        last = point;
        passed = 0;

        for ( ;; )
        {
            FT_Pos u, v;


            if ( on_edge )
            {
                u = point->u;
                if ( u < min_pos )
                {
                    min_pos = u;
                }
                if ( u > max_pos )
                {
                    max_pos = u;
                }

                if ( point->out_dir != segment_dir || point == last )
                {
                    /* we are just leaving an edge; record a new segment! */
                    segment->last = point;
                    segment->pos = ( FT_Short ) (( min_pos + max_pos ) >> 1 );

                    /* a segment is round if either its first or last point */
                    /* is a control point                                   */
                    if (( segment->first->flags | point->flags ) &
                        AF_FLAG_CONTROL )
                    {
                        segment->flags |= AF_EDGE_ROUND;
                    }

                    /* compute segment size */
                    min_pos = max_pos = point->v;

                    v = segment->first->v;
                    if ( v < min_pos )
                    {
                        min_pos = v;
                    }
                    if ( v > max_pos )
                    {
                        max_pos = v;
                    }

                    segment->min_coord = ( FT_Short ) min_pos;
                    segment->max_coord = ( FT_Short ) max_pos;
                    segment->height = ( FT_Short ) ( segment->max_coord -
                                                     segment->min_coord );

                    on_edge = 0;
                    segment = NULL;
                    /* fallthrough */
                }
            }

            /* now exit if we are at the start/end point */
            if ( point == last )
            {
                if ( passed )
                {
                    break;
                }
                passed = 1;
            }

            if ( !on_edge && FT_ABS( point->out_dir ) == major_dir )
            {
                /* this is the start of a new segment! */
                segment_dir = ( AF_Direction ) point->out_dir;

                /* clear all segment fields */
                error = af_axis_hints_new_segment( axis, memory, &segment );
                if ( error )
                {
                    goto Exit;
                }

                segment[ 0 ] = seg0;
                segment->dir = ( FT_Char ) segment_dir;
                min_pos = max_pos = point->u;
                segment->first = point;
                segment->last = point;
                on_edge = 1;
            }

            point = point->next;
        }

    } /* contours */


    /* now slightly increase the height of segments when this makes */
    /* sense -- this is used to better detect and ignore serifs     */
    {
        AF_Segment segments = axis->segments;
        AF_Segment segments_end = segments + axis->num_segments;


        for ( segment = segments; segment < segments_end; segment++ )
        {
            AF_Point first = segment->first;
            AF_Point last = segment->last;
            FT_Pos first_v = first->v;
            FT_Pos last_v = last->v;


            if ( first == last )
            {
                continue;
            }

            if ( first_v < last_v )
            {
                AF_Point p;


                p = first->prev;
                if ( p->v < first_v )
                {
                    segment->height = ( FT_Short ) ( segment->height +
                                                     (( first_v - p->v ) >> 1 ));
                }

                p = last->next;
                if ( p->v > last_v )
                {
                    segment->height = ( FT_Short ) ( segment->height +
                                                     (( p->v - last_v ) >> 1 ));
                }
            }
            else
            {
                AF_Point p;


                p = first->prev;
                if ( p->v > first_v )
                {
                    segment->height = ( FT_Short ) ( segment->height +
                                                     (( p->v - first_v ) >> 1 ));
                }

                p = last->next;
                if ( p->v < last_v )
                {
                    segment->height = ( FT_Short ) ( segment->height +
                                                     (( last_v - p->v ) >> 1 ));
                }
            }
        }
    }

    Exit:
    return error;
}


/* Link segments to form stems and serifs. */

FT_LOCAL_DEF( void )
af_latin_hints_link_segments( AF_GlyphHints hints,
                              AF_Dimension dim )
{
    AF_AxisHints axis = &hints->axis[ dim ];
    AF_Segment segments = axis->segments;
    AF_Segment segment_limit = segments + axis->num_segments;
    FT_Pos len_threshold, len_score;
    AF_Segment seg1, seg2;


    len_threshold = AF_LATIN_CONSTANT( hints->metrics, 8 );
    if ( len_threshold == 0 )
    {
        len_threshold = 1;
    }

    len_score = AF_LATIN_CONSTANT( hints->metrics, 6000 );

    /* now compare each segment to the others */
    for ( seg1 = segments; seg1 < segment_limit; seg1++ )
    {
        /* the fake segments are introduced to hint the metrics -- */
        /* we must never link them to anything                     */
        if ( seg1->dir != axis->major_dir || seg1->first == seg1->last )
        {
            continue;
        }

        /* search for stems having opposite directions, */
        /* with seg1 to the `left' of seg2              */
        for ( seg2 = segments; seg2 < segment_limit; seg2++ )
        {
            FT_Pos pos1 = seg1->pos;
            FT_Pos pos2 = seg2->pos;


            if ( seg1->dir + seg2->dir == 0 && pos2 > pos1 )
            {
                /* compute distance between the two segments */
                FT_Pos dist = pos2 - pos1;
                FT_Pos min = seg1->min_coord;
                FT_Pos max = seg1->max_coord;
                FT_Pos len, score;


                if ( min < seg2->min_coord )
                {
                    min = seg2->min_coord;
                }

                if ( max > seg2->max_coord )
                {
                    max = seg2->max_coord;
                }

                /* compute maximum coordinate difference of the two segments */
                len = max - min;
                if ( len >= len_threshold )
                {
                    /* small coordinate differences cause a higher score, and     */
                    /* segments with a greater distance cause a higher score also */
                    score = dist + len_score / len;

                    /* and we search for the smallest score */
                    /* of the sum of the two values         */
                    if ( score < seg1->score )
                    {
                        seg1->score = score;
                        seg1->link = seg2;
                    }

                    if ( score < seg2->score )
                    {
                        seg2->score = score;
                        seg2->link = seg1;
                    }
                }
            }
        }
    }

    /* now compute the `serif' segments, cf. explanations in `afhints.h' */
    for ( seg1 = segments; seg1 < segment_limit; seg1++ )
    {
        seg2 = seg1->link;

        if ( seg2 )
        {
            if ( seg2->link != seg1 )
            {
                seg1->link = 0;
                seg1->serif = seg2->link;
            }
        }
    }
}


/* Link segments to edges, using feature analysis for selection. */

FT_LOCAL_DEF( FT_Error )
af_latin_hints_compute_edges( AF_GlyphHints hints,
                              AF_Dimension dim )
{
    AF_AxisHints axis = &hints->axis[ dim ];
    FT_Error error = AF_Err_Ok;
    FT_Memory memory = hints->memory;
    AF_LatinAxis laxis = &(( AF_LatinMetrics ) hints->metrics )->axis[ dim ];

    AF_Segment segments = axis->segments;
    AF_Segment segment_limit = segments + axis->num_segments;
    AF_Segment seg;

#if 0
    AF_Direction  up_dir;
#endif
    FT_Fixed scale;
    FT_Pos edge_distance_threshold;
    FT_Pos segment_length_threshold;


    axis->num_edges = 0;

    scale = ( dim == AF_DIMENSION_HORZ ) ? hints->x_scale
                                         : hints->y_scale;

#if 0
    up_dir = ( dim == AF_DIMENSION_HORZ ) ? AF_DIR_UP
                                          : AF_DIR_RIGHT;
#endif

    /*
     *  We ignore all segments that are less than 1 pixel in length
     *  to avoid many problems with serif fonts.  We compute the
     *  corresponding threshold in font units.
     */
    if ( dim == AF_DIMENSION_HORZ )
    {
        segment_length_threshold = FT_DivFix( 64, hints->y_scale );
    }
    else
    {
        segment_length_threshold = 0;
    }

    /*********************************************************************/
    /*                                                                   */
    /* We begin by generating a sorted table of edges for the current    */
    /* direction.  To do so, we simply scan each segment and try to find */
    /* an edge in our table that corresponds to its position.            */
    /*                                                                   */
    /* If no edge is found, we create and insert a new edge in the       */
    /* sorted table.  Otherwise, we simply add the segment to the edge's */
    /* list which gets processed in the second step to compute the       */
    /* edge's properties.                                                */
    /*                                                                   */
    /* Note that the table of edges is sorted along the segment/edge     */
    /* position.                                                         */
    /*                                                                   */
    /*********************************************************************/

    /* assure that edge distance threshold is at most 0.25px */
    edge_distance_threshold = FT_MulFix( laxis->edge_distance_threshold,
                                         scale );
    if ( edge_distance_threshold > 64 / 4 )
    {
        edge_distance_threshold = 64 / 4;
    }

    edge_distance_threshold = FT_DivFix( edge_distance_threshold,
                                         scale );

    for ( seg = segments; seg < segment_limit; seg++ )
    {
        AF_Edge found = NULL;
        FT_Int ee;


        if ( seg->height < segment_length_threshold )
        {
            continue;
        }

        /* A special case for serif edges: If they are smaller than */
        /* 1.5 pixels we ignore them.                               */
        if ( seg->serif &&
             2 * seg->height < 3 * segment_length_threshold )
        {
            continue;
        }

        /* look for an edge corresponding to the segment */
        for ( ee = 0; ee < axis->num_edges; ee++ )
        {
            AF_Edge edge = axis->edges + ee;
            FT_Pos dist;


            dist = seg->pos - edge->fpos;
            if ( dist < 0 )
            {
                dist = -dist;
            }

            if ( dist < edge_distance_threshold && edge->dir == seg->dir )
            {
                found = edge;
                break;
            }
        }

        if ( !found )
        {
            AF_Edge edge;


            /* insert a new edge in the list and */
            /* sort according to the position    */
            error = af_axis_hints_new_edge( axis, seg->pos,
                                            ( AF_Direction ) seg->dir,
                                            memory, &edge );
            if ( error )
            {
                goto Exit;
            }

            /* add the segment to the new edge's list */
            FT_ZERO( edge );

            edge->first = seg;
            edge->last = seg;
            edge->dir = seg->dir;
            edge->fpos = seg->pos;
            edge->opos = FT_MulFix( seg->pos, scale );
            edge->pos = edge->opos;
            seg->edge_next = seg;
        }
        else
        {
            /* if an edge was found, simply add the segment to the edge's */
            /* list                                                       */
            seg->edge_next = found->first;
            found->last->edge_next = seg;
            found->last = seg;
        }
    }


    /*********************************************************************/
    /*                                                                   */
    /* Good, we will now compute each edge's properties according to     */
    /* the segments found on its position.  Basically, these are         */
    /*                                                                   */
    /*  - the edge's main direction                                      */
    /*  - stem edge, serif edge or both (which defaults to stem then)    */
    /*  - rounded edge, straight or both (which defaults to straight)    */
    /*  - link for edge                                                  */
    /*                                                                   */
    /*********************************************************************/

    /* first of all, set the `edge' field in each segment -- this is */
    /* required in order to compute edge links                       */

    /*
     * Note that removing this loop and setting the `edge' field of each
     * segment directly in the code above slows down execution speed for
     * some reasons on platforms like the Sun.
     */
    {
        AF_Edge edges = axis->edges;
        AF_Edge edge_limit = edges + axis->num_edges;
        AF_Edge edge;


        for ( edge = edges; edge < edge_limit; edge++ )
        {
            seg = edge->first;
            if ( seg )
            {
                do
                {
                    seg->edge = edge;
                    seg = seg->edge_next;

                }
                while ( seg != edge->first );
            }
        }

        /* now compute each edge properties */
        for ( edge = edges; edge < edge_limit; edge++ )
        {
            FT_Int is_round = 0;  /* does it contain round segments?    */
            FT_Int is_straight = 0;  /* does it contain straight segments? */
#if 0
            FT_Pos  ups         = 0;  /* number of upwards segments         */
            FT_Pos  downs       = 0;  /* number of downwards segments       */
#endif


            seg = edge->first;

            do
            {
                FT_Bool is_serif;


                /* check for roundness of segment */
                if ( seg->flags & AF_EDGE_ROUND )
                {
                    is_round++;
                }
                else
                {
                    is_straight++;
                }

#if 0
                /* check for segment direction */
                if ( seg->dir == up_dir )
                  ups   += seg->max_coord - seg->min_coord;
                else
                  downs += seg->max_coord - seg->min_coord;
#endif

                /* check for links -- if seg->serif is set, then seg->link must */
                /* be ignored                                                   */
                is_serif = ( FT_Bool ) ( seg->serif &&
                                         seg->serif->edge &&
                                         seg->serif->edge != edge );

                if (( seg->link && seg->link->edge != NULL) || is_serif )
                {
                    AF_Edge edge2;
                    AF_Segment seg2;


                    edge2 = edge->link;
                    seg2 = seg->link;

                    if ( is_serif )
                    {
                        seg2 = seg->serif;
                        edge2 = edge->serif;
                    }

                    if ( edge2 )
                    {
                        FT_Pos edge_delta;
                        FT_Pos seg_delta;


                        edge_delta = edge->fpos - edge2->fpos;
                        if ( edge_delta < 0 )
                        {
                            edge_delta = -edge_delta;
                        }

                        seg_delta = seg->pos - seg2->pos;
                        if ( seg_delta < 0 )
                        {
                            seg_delta = -seg_delta;
                        }

                        if ( seg_delta < edge_delta )
                        {
                            edge2 = seg2->edge;
                        }
                    }
                    else
                    {
                        edge2 = seg2->edge;
                    }

                    if ( is_serif )
                    {
                        edge->serif = edge2;
                        edge2->flags |= AF_EDGE_SERIF;
                    }
                    else
                    {
                        edge->link = edge2;
                    }
                }

                seg = seg->edge_next;

            }
            while ( seg != edge->first );

            /* set the round/straight flags */
            edge->flags = AF_EDGE_NORMAL;

            if ( is_round > 0 && is_round >= is_straight )
            {
                edge->flags |= AF_EDGE_ROUND;
            }

#if 0
            /* set the edge's main direction */
            edge->dir = AF_DIR_NONE;

            if ( ups > downs )
              edge->dir = (FT_Char)up_dir;

            else if ( ups < downs )
              edge->dir = (FT_Char)-up_dir;

            else if ( ups == downs )
              edge->dir = 0;  /* both up and down! */
#endif

            /* get rid of serifs if link is set                 */
            /* XXX: This gets rid of many unpleasant artefacts! */
            /*      Example: the `c' in cour.pfa at size 13     */

            if ( edge->serif && edge->link )
            {
                edge->serif = 0;
            }
        }
    }

    Exit:
    return error;
}


/* Detect segments and edges for given dimension. */

FT_LOCAL_DEF( FT_Error )
af_latin_hints_detect_features( AF_GlyphHints hints,
                                AF_Dimension dim )
{
    FT_Error error;


    error = af_latin_hints_compute_segments( hints, dim );
    if ( !error )
    {
        af_latin_hints_link_segments( hints, dim );

        error = af_latin_hints_compute_edges( hints, dim );
    }

    return error;
}


/* Compute all edges which lie within blue zones. */

FT_LOCAL_DEF( void )
af_latin_hints_compute_blue_edges( AF_GlyphHints hints,
                                   AF_LatinMetrics metrics )
{
    AF_AxisHints axis = &hints->axis[ AF_DIMENSION_VERT ];
    AF_Edge edge = axis->edges;
    AF_Edge edge_limit = edge + axis->num_edges;
    AF_LatinAxis latin = &metrics->axis[ AF_DIMENSION_VERT ];
    FT_Fixed scale = latin->scale;


    /* compute which blue zones are active, i.e. have their scaled */
    /* size < 3/4 pixels                                           */

    /* for each horizontal edge search the blue zone which is closest */
    for ( ; edge < edge_limit; edge++ )
    {
        FT_Int bb;
        AF_Width best_blue = NULL;
        FT_Pos best_dist;  /* initial threshold */


        /* compute the initial threshold as a fraction of the EM size */
        /* (the value 40 is heuristic)                                */
        best_dist = FT_MulFix( metrics->units_per_em / 40, scale );

        /* assure a minimum distance of 0.5px */
        if ( best_dist > 64 / 2 )
        {
            best_dist = 64 / 2;
        }

        for ( bb = 0; bb < AF_LATIN_BLUE_MAX; bb++ )
        {
            AF_LatinBlue blue = latin->blues + bb;
            FT_Bool is_top_blue, is_major_dir;


            /* skip inactive blue zones (i.e., those that are too large) */
            if ( !( blue->flags & AF_LATIN_BLUE_ACTIVE ))
            {
                continue;
            }

            /* if it is a top zone, check for right edges -- if it is a bottom */
            /* zone, check for left edges                                      */
            /*                                                                 */
            /* of course, that's for TrueType                                  */
            is_top_blue = ( FT_Byte ) (( blue->flags & AF_LATIN_BLUE_TOP ) != 0 );
            is_major_dir = FT_BOOL( edge->dir == axis->major_dir );

            /* if it is a top zone, the edge must be against the major    */
            /* direction; if it is a bottom zone, it must be in the major */
            /* direction                                                  */
            if ( is_top_blue ^ is_major_dir )
            {
                FT_Pos dist;


                /* first of all, compare it to the reference position */
                dist = edge->fpos - blue->ref.org;
                if ( dist < 0 )
                {
                    dist = -dist;
                }

                dist = FT_MulFix( dist, scale );
                if ( dist < best_dist )
                {
                    best_dist = dist;
                    best_blue = &blue->ref;
                }

                /* now compare it to the overshoot position and check whether */
                /* the edge is rounded, and whether the edge is over the      */
                /* reference position of a top zone, or under the reference   */
                /* position of a bottom zone                                  */
                if ( edge->flags & AF_EDGE_ROUND && dist != 0 )
                {
                    FT_Bool is_under_ref = FT_BOOL( edge->fpos < blue->ref.org );


                    if ( is_top_blue ^ is_under_ref )
                    {
                        dist = edge->fpos - blue->shoot.org;
                        if ( dist < 0 )
                        {
                            dist = -dist;
                        }

                        dist = FT_MulFix( dist, scale );
                        if ( dist < best_dist )
                        {
                            best_dist = dist;
                            best_blue = &blue->shoot;
                        }
                    }
                }
            }
        }

        if ( best_blue )
        {
            edge->blue_edge = best_blue;
        }
    }
}


/* Initalize hinting engine. */

static FT_Error
af_latin_hints_init( AF_GlyphHints hints,
                     AF_LatinMetrics metrics )
{
    FT_Render_Mode mode;
    FT_UInt32 scaler_flags, other_flags;
    FT_Face face = metrics->root.scaler.face;


    af_glyph_hints_rescale( hints, ( AF_ScriptMetrics ) metrics );

    /*
     *  correct x_scale and y_scale if needed, since they may have
     *  been modified by `af_latin_metrics_scale_dim' above
     */
    hints->x_scale = metrics->axis[ AF_DIMENSION_HORZ ].scale;
    hints->x_delta = metrics->axis[ AF_DIMENSION_HORZ ].delta;
    hints->y_scale = metrics->axis[ AF_DIMENSION_VERT ].scale;
    hints->y_delta = metrics->axis[ AF_DIMENSION_VERT ].delta;

    /* compute flags depending on render mode, etc. */
    mode = metrics->root.scaler.render_mode;

#if 0 /* #ifdef AF_CONFIG_OPTION_USE_WARPER */
    if ( mode == FT_RENDER_MODE_LCD || mode == FT_RENDER_MODE_LCD_V )
    {
      metrics->root.scaler.render_mode = mode = FT_RENDER_MODE_NORMAL;
    }
#endif

    scaler_flags = hints->scaler_flags;
    other_flags = 0;

    /*
     *  We snap the width of vertical stems for the monochrome and
     *  horizontal LCD rendering targets only.
     */
    if ( mode == FT_RENDER_MODE_MONO || mode == FT_RENDER_MODE_LCD )
    {
        other_flags |= AF_LATIN_HINTS_HORZ_SNAP;
    }

    /*
     *  We snap the width of horizontal stems for the monochrome and
     *  vertical LCD rendering targets only.
     */
    if ( mode == FT_RENDER_MODE_MONO || mode == FT_RENDER_MODE_LCD_V )
    {
        other_flags |= AF_LATIN_HINTS_VERT_SNAP;
    }

    /*
     *  We adjust stems to full pixels only if we don't use the `light' mode.
     */
    if ( mode != FT_RENDER_MODE_LIGHT )
    {
        other_flags |= AF_LATIN_HINTS_STEM_ADJUST;
    }

    if ( mode == FT_RENDER_MODE_MONO )
    {
        other_flags |= AF_LATIN_HINTS_MONO;
    }

    /*
     *  In `light' hinting mode we disable horizontal hinting completely.
     *  We also do it if the face is italic.
     */
    if ( mode == FT_RENDER_MODE_LIGHT ||
         ( face->style_flags & FT_STYLE_FLAG_ITALIC) != 0 )
    {
        scaler_flags |= AF_SCALER_FLAG_NO_HORIZONTAL;
    }

    hints->scaler_flags = scaler_flags;
    hints->other_flags = other_flags;

    return AF_Err_Ok;
}


/*************************************************************************/
/*************************************************************************/
/*****                                                               *****/
/*****        L A T I N   G L Y P H   G R I D - F I T T I N G        *****/
/*****                                                               *****/
/*************************************************************************/
/*************************************************************************/

/* Snap a given width in scaled coordinates to one of the */
/* current standard widths.                               */

static FT_Pos
af_latin_snap_width( AF_Width widths,
                     FT_Int count,
                     FT_Pos width )
{
    int n;
    FT_Pos best = 64 + 32 + 2;
    FT_Pos reference = width;
    FT_Pos scaled;


    for ( n = 0; n < count; n++ )
    {
        FT_Pos w;
        FT_Pos dist;


        w = widths[ n ].cur;
        dist = width - w;
        if ( dist < 0 )
        {
            dist = -dist;
        }
        if ( dist < best )
        {
            best = dist;
            reference = w;
        }
    }

    scaled = FT_PIX_ROUND( reference );

    if ( width >= reference )
    {
        if ( width < scaled + 48 )
        {
            width = reference;
        }
    }
    else
    {
        if ( width > scaled - 48 )
        {
            width = reference;
        }
    }

    return width;
}


/* Compute the snapped width of a given stem, ignoring very thin ones. */
/* There is a lot of voodoo in this function; changing the hard-coded  */
/* parameters influence the whole hinting process.                     */

static FT_Pos
af_latin_compute_stem_width( AF_GlyphHints hints,
                             AF_Dimension dim,
                             FT_Pos width,
                             AF_Edge_Flags base_flags,
                             AF_Edge_Flags stem_flags )
{
    AF_LatinMetrics metrics = ( AF_LatinMetrics ) hints->metrics;
    AF_LatinAxis axis = &metrics->axis[ dim ];
    FT_Pos dist = width;
    FT_Int sign = 0;
    FT_Int vertical = ( dim == AF_DIMENSION_VERT );


    if ( !AF_LATIN_HINTS_DO_STEM_ADJUST( hints ) ||
         axis->extra_light )
    {
        return width;
    }

    if ( dist < 0 )
    {
        dist = -width;
        sign = 1;
    }

    if (( vertical && !AF_LATIN_HINTS_DO_VERT_SNAP( hints )) ||
        ( !vertical && !AF_LATIN_HINTS_DO_HORZ_SNAP( hints )))
    {
        /* smooth hinting process: very lightly quantize the stem width */

        /* leave the widths of serifs alone */
        if (( stem_flags & AF_EDGE_SERIF ) &&
            vertical &&
            ( dist < 3 * 64 ))
        {
            goto Done_Width;
        }

        else if ( base_flags & AF_EDGE_ROUND )
        {
            if ( dist < 80 )
            {
                dist = 64;
            }
        }
        else if ( dist < 56 )
        {
            dist = 56;
        }

        if ( axis->width_count > 0 )
        {
            FT_Pos delta;


            /* compare to standard width */
            delta = dist - axis->widths[ 0 ].cur;

            if ( delta < 0 )
            {
                delta = -delta;
            }

            if ( delta < 40 )
            {
                dist = axis->widths[ 0 ].cur;
                if ( dist < 48 )
                {
                    dist = 48;
                }

                goto Done_Width;
            }

            if ( dist < 3 * 64 )
            {
                delta = dist & 63;
                dist &= -64;

                if ( delta < 10 )
                {
                    dist += delta;
                }

                else if ( delta < 32 )
                {
                    dist += 10;
                }

                else if ( delta < 54 )
                {
                    dist += 54;
                }

                else
                {
                    dist += delta;
                }
            }
            else
            {
                dist = ( dist + 32 ) & ~63;
            }
        }
    }
    else
    {
        /* strong hinting process: snap the stem width to integer pixels */

        FT_Pos org_dist = dist;


        dist = af_latin_snap_width( axis->widths, axis->width_count, dist );

        if ( vertical )
        {
            /* in the case of vertical hinting, always round */
            /* the stem heights to integer pixels            */

            if ( dist >= 64 )
            {
                dist = ( dist + 16 ) & ~63;
            }
            else
            {
                dist = 64;
            }
        }
        else
        {
            if ( AF_LATIN_HINTS_DO_MONO( hints ))
            {
                /* monochrome horizontal hinting: snap widths to integer pixels */
                /* with a different threshold                                   */

                if ( dist < 64 )
                {
                    dist = 64;
                }
                else
                {
                    dist = ( dist + 32 ) & ~63;
                }
            }
            else
            {
                /* for horizontal anti-aliased hinting, we adopt a more subtle */
                /* approach: we strengthen small stems, round stems whose size */
                /* is between 1 and 2 pixels to an integer, otherwise nothing  */

                if ( dist < 48 )
                {
                    dist = ( dist + 64 ) >> 1;
                }

                else if ( dist < 128 )
                {
                    /* We only round to an integer width if the corresponding */
                    /* distortion is less than 1/4 pixel.  Otherwise this     */
                    /* makes everything worse since the diagonals, which are  */
                    /* not hinted, appear a lot bolder or thinner than the    */
                    /* vertical stems.                                        */

                    FT_Pos delta;


                    dist = ( dist + 22 ) & ~63;
                    delta = dist - org_dist;
                    if ( delta < 0 )
                    {
                        delta = -delta;
                    }

                    if ( delta >= 16 )
                    {
                        dist = org_dist;
                        if ( dist < 48 )
                        {
                            dist = ( dist + 64 ) >> 1;
                        }
                    }
                }
                else
                {
                    /* round otherwise to prevent color fringes in LCD mode */
                    dist = ( dist + 32 ) & ~63;
                }
            }
        }
    }

    Done_Width:
    if ( sign )
    {
        dist = -dist;
    }

    return dist;
}


/* Align one stem edge relative to the previous stem edge. */

static void
af_latin_align_linked_edge( AF_GlyphHints hints,
                            AF_Dimension dim,
                            AF_Edge base_edge,
                            AF_Edge stem_edge )
{
    FT_Pos dist = stem_edge->opos - base_edge->opos;

    FT_Pos fitted_width = af_latin_compute_stem_width(
            hints, dim, dist,
            ( AF_Edge_Flags ) base_edge->flags,
            ( AF_Edge_Flags ) stem_edge->flags );


    stem_edge->pos = base_edge->pos + fitted_width;

    FT_TRACE5(( "  LINK: edge %d (opos=%.2f) linked to (%.2f),"
                " dist was %.2f, now %.2f\n",
            stem_edge - hints->axis[ dim ].edges, stem_edge->opos / 64.0,
            stem_edge->pos / 64.0, dist / 64.0, fitted_width / 64.0 ));
}


/* Shift the coordinates of the `serif' edge by the same amount */
/* as the corresponding `base' edge has been moved already.     */

static void
af_latin_align_serif_edge( AF_GlyphHints hints,
                           AF_Edge base,
                           AF_Edge serif )
{
    FT_UNUSED( hints );

    serif->pos = base->pos + ( serif->opos - base->opos );
}


/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/****                                                                 ****/
/****                    E D G E   H I N T I N G                      ****/
/****                                                                 ****/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/


/* The main grid-fitting routine. */

FT_LOCAL_DEF( void )
af_latin_hint_edges( AF_GlyphHints hints,
                     AF_Dimension dim )
{
    AF_AxisHints axis = &hints->axis[ dim ];
    AF_Edge edges = axis->edges;
    AF_Edge edge_limit = edges + axis->num_edges;
    FT_PtrDist n_edges;
    AF_Edge edge;
    AF_Edge anchor = NULL;
    FT_Int has_serifs = 0;


    FT_TRACE5(( "%s edge hinting\n", dim == AF_DIMENSION_VERT ? "horizontal"
                                                              : "vertical" ));

    /* we begin by aligning all stems relative to the blue zone */
    /* if needed -- that's only for horizontal edges            */

    if ( dim == AF_DIMENSION_VERT && AF_HINTS_DO_BLUES( hints ) )
    {
        for ( edge = edges; edge < edge_limit; edge++ )
        {
            AF_Width blue;
            AF_Edge edge1, edge2; /* these edges form the stem to check */


            if ( edge->flags & AF_EDGE_DONE )
            {
                continue;
            }

            blue = edge->blue_edge;
            edge1 = NULL;
            edge2 = edge->link;

            if ( blue )
            {
                edge1 = edge;

                /* flip edges if the other stem is aligned to a blue zone */
            }
            else if ( edge2 && edge2->blue_edge )
            {
                blue = edge2->blue_edge;
                edge1 = edge2;
                edge2 = edge;
            }

            if ( !edge1 )
            {
                continue;
            }

            FT_TRACE5(( "  BLUE: edge %d (opos=%.2f) snapped to (%.2f),"
                        " was (%.2f)\n",
                    edge1 - edges, edge1->opos / 64.0, blue->fit / 64.0,
                    edge1->pos / 64.0 ));

            edge1->pos = blue->fit;
            edge1->flags |= AF_EDGE_DONE;

            if ( edge2 && !edge2->blue_edge )
            {
                af_latin_align_linked_edge( hints, dim, edge1, edge2 );
                edge2->flags |= AF_EDGE_DONE;
            }

            if ( !anchor )
            {
                anchor = edge;
            }
        }
    }

    /* now we align all other stem edges, trying to maintain the */
    /* relative order of stems in the glyph                      */
    for ( edge = edges; edge < edge_limit; edge++ )
    {
        AF_Edge edge2;


        if ( edge->flags & AF_EDGE_DONE )
        {
            continue;
        }

        /* skip all non-stem edges */
        edge2 = edge->link;
        if ( !edge2 )
        {
            has_serifs++;
            continue;
        }

        /* now align the stem */

        /* this should not happen, but it's better to be safe */
        if ( edge2->blue_edge )
        {
            FT_TRACE5(( "  ASSERTION FAILED for edge %d\n", edge2 - edges ));

            af_latin_align_linked_edge( hints, dim, edge2, edge );
            edge->flags |= AF_EDGE_DONE;
            continue;
        }

        if ( !anchor )
        {
            /* if we reach this if clause, no stem has been aligned yet */

            FT_Pos org_len, org_center, cur_len;
            FT_Pos cur_pos1, error1, error2, u_off, d_off;


            org_len = edge2->opos - edge->opos;
            cur_len = af_latin_compute_stem_width(
                    hints, dim, org_len,
                    ( AF_Edge_Flags ) edge->flags,
                    ( AF_Edge_Flags ) edge2->flags );

            /* some voodoo to specially round edges for small stem widths; */
            /* the idea is to align the center of a stem, then shifting    */
            /* the stem edges to suitable positions                        */
            if ( cur_len <= 64 )
            {
                /* width <= 1px */
                u_off = 32;
                d_off = 32;
            }
            else
            {
                /* 1px < width < 1.5px */
                u_off = 38;
                d_off = 26;
            }

            if ( cur_len < 96 )
            {
                org_center = edge->opos + ( org_len >> 1 );
                cur_pos1 = FT_PIX_ROUND( org_center );

                error1 = org_center - ( cur_pos1 - u_off );
                if ( error1 < 0 )
                {
                    error1 = -error1;
                }

                error2 = org_center - ( cur_pos1 + d_off );
                if ( error2 < 0 )
                {
                    error2 = -error2;
                }

                if ( error1 < error2 )
                {
                    cur_pos1 -= u_off;
                }
                else
                {
                    cur_pos1 += d_off;
                }

                edge->pos = cur_pos1 - cur_len / 2;
                edge2->pos = edge->pos + cur_len;
            }
            else
            {
                edge->pos = FT_PIX_ROUND( edge->opos );
            }

            FT_TRACE5(( "  ANCHOR: edge %d (opos=%.2f) and %d (opos=%.2f)"
                        " snapped to (%.2f) (%.2f)\n",
                    edge - edges, edge->opos / 64.0,
                    edge2 - edges, edge2->opos / 64.0,
                    edge->pos / 64.0, edge2->pos / 64.0 ));
            anchor = edge;

            edge->flags |= AF_EDGE_DONE;

            af_latin_align_linked_edge( hints, dim, edge, edge2 );
        }
        else
        {
            FT_Pos org_pos, org_len, org_center, cur_len;
            FT_Pos cur_pos1, cur_pos2, delta1, delta2;


            org_pos = anchor->pos + ( edge->opos - anchor->opos );
            org_len = edge2->opos - edge->opos;
            org_center = org_pos + ( org_len >> 1 );

            cur_len = af_latin_compute_stem_width(
                    hints, dim, org_len,
                    ( AF_Edge_Flags ) edge->flags,
                    ( AF_Edge_Flags ) edge2->flags );

            if ( edge2->flags & AF_EDGE_DONE )
            {
                FT_TRACE5(( "  ADJUST: edge %d (pos=%.2f) moved to %.2f\n",
                        edge - edges, edge->pos / 64.0,
                        ( edge2->pos - cur_len ) / 64.0 ));

                edge->pos = edge2->pos - cur_len;
            }

            else if ( cur_len < 96 )
            {
                FT_Pos u_off, d_off;


                cur_pos1 = FT_PIX_ROUND( org_center );

                if ( cur_len <= 64 )
                {
                    u_off = 32;
                    d_off = 32;
                }
                else
                {
                    u_off = 38;
                    d_off = 26;
                }

                delta1 = org_center - ( cur_pos1 - u_off );
                if ( delta1 < 0 )
                {
                    delta1 = -delta1;
                }

                delta2 = org_center - ( cur_pos1 + d_off );
                if ( delta2 < 0 )
                {
                    delta2 = -delta2;
                }

                if ( delta1 < delta2 )
                {
                    cur_pos1 -= u_off;
                }
                else
                {
                    cur_pos1 += d_off;
                }

                edge->pos = cur_pos1 - cur_len / 2;
                edge2->pos = cur_pos1 + cur_len / 2;

                FT_TRACE5(( "  STEM: %d (opos=%.2f) to %d (opos=%.2f)"
                            " snapped to (%.2f) and (%.2f)\n",
                        edge - edges, edge->opos / 64.0,
                        edge2 - edges, edge2->opos / 64.0,
                        edge->pos / 64.0, edge2->pos / 64.0 ));
            }
            else
            {
                org_pos = anchor->pos + ( edge->opos - anchor->opos );
                org_len = edge2->opos - edge->opos;
                org_center = org_pos + ( org_len >> 1 );

                cur_len = af_latin_compute_stem_width(
                        hints, dim, org_len,
                        ( AF_Edge_Flags ) edge->flags,
                        ( AF_Edge_Flags ) edge2->flags );

                cur_pos1 = FT_PIX_ROUND( org_pos );
                delta1 = cur_pos1 + ( cur_len >> 1 ) - org_center;
                if ( delta1 < 0 )
                {
                    delta1 = -delta1;
                }

                cur_pos2 = FT_PIX_ROUND( org_pos + org_len ) - cur_len;
                delta2 = cur_pos2 + ( cur_len >> 1 ) - org_center;
                if ( delta2 < 0 )
                {
                    delta2 = -delta2;
                }

                edge->pos = ( delta1 < delta2 ) ? cur_pos1 : cur_pos2;
                edge2->pos = edge->pos + cur_len;

                FT_TRACE5(( "  STEM: %d (opos=%.2f) to %d (opos=%.2f)"
                            " snapped to (%.2f) and (%.2f)\n",
                        edge - edges, edge->opos / 64.0,
                        edge2 - edges, edge2->opos / 64.0,
                        edge->pos / 64.0, edge2->pos / 64.0 ));
            }

            edge->flags |= AF_EDGE_DONE;
            edge2->flags |= AF_EDGE_DONE;

            if ( edge > edges && edge->pos < edge[ -1 ].pos )
            {
                FT_TRACE5(( "  BOUND: %d (pos=%.2f) to (%.2f)\n",
                        edge - edges, edge->pos / 64.0, edge[ -1 ].pos / 64.0 ));
                edge->pos = edge[ -1 ].pos;
            }
        }
    }

    /* make sure that lowercase m's maintain their symmetry */

    /* In general, lowercase m's have six vertical edges if they are sans */
    /* serif, or twelve if they are with serifs.  This implementation is  */
    /* based on that assumption, and seems to work very well with most    */
    /* faces.  However, if for a certain face this assumption is not      */
    /* true, the m is just rendered like before.  In addition, any stem   */
    /* correction will only be applied to symmetrical glyphs (even if the */
    /* glyph is not an m), so the potential for unwanted distortion is    */
    /* relatively low.                                                    */

    /* We don't handle horizontal edges since we can't easily assure that */
    /* the third (lowest) stem aligns with the base line; it might end up */
    /* one pixel higher or lower.                                         */

    n_edges = edge_limit - edges;
    if ( dim == AF_DIMENSION_HORZ && ( n_edges == 6 || n_edges == 12 ))
    {
        AF_Edge edge1, edge2, edge3;
        FT_Pos dist1, dist2, span, delta;


        if ( n_edges == 6 )
        {
            edge1 = edges;
            edge2 = edges + 2;
            edge3 = edges + 4;
        }
        else
        {
            edge1 = edges + 1;
            edge2 = edges + 5;
            edge3 = edges + 9;
        }

        dist1 = edge2->opos - edge1->opos;
        dist2 = edge3->opos - edge2->opos;

        span = dist1 - dist2;
        if ( span < 0 )
        {
            span = -span;
        }

        if ( span < 8 )
        {
            delta = edge3->pos - ( 2 * edge2->pos - edge1->pos );
            edge3->pos -= delta;
            if ( edge3->link )
            {
                edge3->link->pos -= delta;
            }

            /* move the serifs along with the stem */
            if ( n_edges == 12 )
            {
                ( edges + 8 )->pos -= delta;
                ( edges + 11 )->pos -= delta;
            }

            edge3->flags |= AF_EDGE_DONE;
            if ( edge3->link )
            {
                edge3->link->flags |= AF_EDGE_DONE;
            }
        }
    }

    if ( has_serifs || !anchor )
    {
        /*
         *  now hint the remaining edges (serifs and single) in order
         *  to complete our processing
         */
        for ( edge = edges; edge < edge_limit; edge++ )
        {
            FT_Pos delta;


            if ( edge->flags & AF_EDGE_DONE )
            {
                continue;
            }

            delta = 1000;

            if ( edge->serif )
            {
                delta = edge->serif->opos - edge->opos;
                if ( delta < 0 )
                {
                    delta = -delta;
                }
            }

            if ( delta < 64 + 16 )
            {
                af_latin_align_serif_edge( hints, edge->serif, edge );
                FT_TRACE5(( "  SERIF: edge %d (opos=%.2f) serif to %d (opos=%.2f)"
                            " aligned to (%.2f)\n",
                        edge - edges, edge->opos / 64.0,
                        edge->serif - edges, edge->serif->opos / 64.0,
                        edge->pos / 64.0 ));
            }
            else if ( !anchor )
            {
                edge->pos = FT_PIX_ROUND( edge->opos );
                anchor = edge;
                FT_TRACE5(( "  SERIF_ANCHOR: edge %d (opos=%.2f)"
                            " snapped to (%.2f)\n",
                        edge - edges, edge->opos / 64.0, edge->pos / 64.0 ));
            }
            else
            {
                AF_Edge before, after;


                for ( before = edge - 1; before >= edges; before-- )
                {
                    if ( before->flags & AF_EDGE_DONE )
                    {
                        break;
                    }
                }

                for ( after = edge + 1; after < edge_limit; after++ )
                {
                    if ( after->flags & AF_EDGE_DONE )
                    {
                        break;
                    }
                }

                if ( before >= edges && before < edge &&
                     after < edge_limit && after > edge )
                {
                    if ( after->opos == before->opos )
                    {
                        edge->pos = before->pos;
                    }
                    else
                    {
                        edge->pos = before->pos +
                                    FT_MulDiv( edge->opos - before->opos,
                                               after->pos - before->pos,
                                               after->opos - before->opos );
                    }

                    FT_TRACE5(( "  SERIF_LINK1: edge %d (opos=%.2f) snapped to (%.2f)"
                                " from %d (opos=%.2f)\n",
                            edge - edges, edge->opos / 64.0,
                            edge->pos / 64.0,
                            before - edges, before->opos / 64.0 ));
                }
                else
                {
                    edge->pos = anchor->pos +
                                (( edge->opos - anchor->opos + 16 ) & ~31 );

                    FT_TRACE5(( "  SERIF_LINK2: edge %d (opos=%.2f)"
                                " snapped to (%.2f)\n",
                            edge - edges, edge->opos / 64.0, edge->pos / 64.0 ));
                }
            }

            edge->flags |= AF_EDGE_DONE;

            if ( edge > edges && edge->pos < edge[ -1 ].pos )
            {
                edge->pos = edge[ -1 ].pos;
            }

            if ( edge + 1 < edge_limit &&
                 edge[ 1 ].flags & AF_EDGE_DONE &&
                 edge->pos > edge[ 1 ].pos )
            {
                edge->pos = edge[ 1 ].pos;
            }
        }
    }

    FT_TRACE5(( "\n" ));
}


/* Apply the complete hinting algorithm to a latin glyph. */

static FT_Error
af_latin_hints_apply( AF_GlyphHints hints,
                      FT_Outline *outline,
                      AF_LatinMetrics metrics )
{
    FT_Error error;
    int dim;


    error = af_glyph_hints_reload( hints, outline );
    if ( error )
    {
        goto Exit;
    }

    /* analyze glyph outline */
#ifdef AF_CONFIG_OPTION_USE_WARPER
    if ( metrics->root.scaler.render_mode == FT_RENDER_MODE_LIGHT ||
         AF_HINTS_DO_HORIZONTAL( hints )                          )
#else
    if ( AF_HINTS_DO_HORIZONTAL( hints ))
#endif
    {
        error = af_latin_hints_detect_features( hints, AF_DIMENSION_HORZ );
        if ( error )
        {
            goto Exit;
        }
    }

    if ( AF_HINTS_DO_VERTICAL( hints ))
    {
        error = af_latin_hints_detect_features( hints, AF_DIMENSION_VERT );
        if ( error )
        {
            goto Exit;
        }

        af_latin_hints_compute_blue_edges( hints, metrics );
    }

    /* grid-fit the outline */
    for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ )
    {
#ifdef AF_CONFIG_OPTION_USE_WARPER
        if ( dim == AF_DIMENSION_HORZ                                 &&
             metrics->root.scaler.render_mode == FT_RENDER_MODE_LIGHT )
        {
          AF_WarperRec  warper;
          FT_Fixed      scale;
          FT_Pos        delta;


          af_warper_compute( &warper, hints, (AF_Dimension)dim,
                             &scale, &delta );
          af_glyph_hints_scale_dim( hints, (AF_Dimension)dim,
                                    scale, delta );
          continue;
        }
#endif

        if (( dim == AF_DIMENSION_HORZ && AF_HINTS_DO_HORIZONTAL( hints )) ||
            ( dim == AF_DIMENSION_VERT && AF_HINTS_DO_VERTICAL( hints )))
        {
            af_latin_hint_edges( hints, ( AF_Dimension ) dim );
            af_glyph_hints_align_edge_points( hints, ( AF_Dimension ) dim );
            af_glyph_hints_align_strong_points( hints, ( AF_Dimension ) dim );
            af_glyph_hints_align_weak_points( hints, ( AF_Dimension ) dim );
        }
    }
    af_glyph_hints_save( hints, outline );

    Exit:
    return error;
}


/*************************************************************************/
/*************************************************************************/
/*****                                                               *****/
/*****              L A T I N   S C R I P T   C L A S S              *****/
/*****                                                               *****/
/*************************************************************************/
/*************************************************************************/


/* XXX: this should probably fine tuned to differentiate better between */
/*      scripts...                                                      */

static const AF_Script_UniRangeRec af_latin_uniranges[] =
        {
                AF_UNIRANGE_REC( 0x0020UL, 0x007FUL ),  /* Basic Latin (no control chars) */
                AF_UNIRANGE_REC( 0x00A0UL, 0x00FFUL ),  /* Latin-1 Supplement (no control chars) */
                AF_UNIRANGE_REC( 0x0100UL, 0x017FUL ),  /* Latin Extended-A */
                AF_UNIRANGE_REC( 0x0180UL, 0x024FUL ),  /* Latin Extended-B */
                AF_UNIRANGE_REC( 0x0250UL, 0x02AFUL ),  /* IPA Extensions */
                AF_UNIRANGE_REC( 0x02B0UL, 0x02FFUL ),  /* Spacing Modifier Letters */
                AF_UNIRANGE_REC( 0x0300UL, 0x036FUL ),  /* Combining Diacritical Marks */
                AF_UNIRANGE_REC( 0x0370UL, 0x03FFUL ),  /* Greek and Coptic */
                AF_UNIRANGE_REC( 0x0400UL, 0x04FFUL ),  /* Cyrillic */
                AF_UNIRANGE_REC( 0x0500UL, 0x052FUL ),  /* Cyrillic Supplement */
                AF_UNIRANGE_REC( 0x1D00UL, 0x1D7FUL ),  /* Phonetic Extensions */
                AF_UNIRANGE_REC( 0x1D80UL, 0x1DBFUL ),  /* Phonetic Extensions Supplement */
                AF_UNIRANGE_REC( 0x1DC0UL, 0x1DFFUL ),  /* Combining Diacritical Marks Supplement */
                AF_UNIRANGE_REC( 0x1E00UL, 0x1EFFUL ),  /* Latin Extended Additional */
                AF_UNIRANGE_REC( 0x1F00UL, 0x1FFFUL ),  /* Greek Extended */
                AF_UNIRANGE_REC( 0x2000UL, 0x206FUL ),  /* General Punctuation */
                AF_UNIRANGE_REC( 0x2070UL, 0x209FUL ),  /* Superscripts and Subscripts */
                AF_UNIRANGE_REC( 0x20A0UL, 0x20CFUL ),  /* Currency Symbols */
                AF_UNIRANGE_REC( 0x2150UL, 0x218FUL ),  /* Number Forms */
                AF_UNIRANGE_REC( 0x2460UL, 0x24FFUL ),  /* Enclosed Alphanumerics */
                AF_UNIRANGE_REC( 0x2C60UL, 0x2C7FUL ),  /* Latin Extended-C */
                AF_UNIRANGE_REC( 0x2DE0UL, 0x2DFFUL ),  /* Cyrillic Extended-A */
                AF_UNIRANGE_REC( 0xA640UL, 0xA69FUL ),  /* Cyrillic Extended-B */
                AF_UNIRANGE_REC( 0xA720UL, 0xA7FFUL ),  /* Latin Extended-D */
                AF_UNIRANGE_REC( 0xFB00UL, 0xFB06UL ),  /* Alphab. Present. Forms (Latin Ligs) */
                AF_UNIRANGE_REC( 0x1D400UL, 0x1D7FFUL ),  /* Mathematical Alphanumeric Symbols */
                AF_UNIRANGE_REC( 0UL, 0UL )
        };


AF_DEFINE_SCRIPT_CLASS( af_latin_script_class,
                        AF_SCRIPT_LATIN,
                        af_latin_uniranges,

                        sizeof( AF_LatinMetricsRec ),

                        ( AF_Script_InitMetricsFunc ) af_latin_metrics_init,
                        ( AF_Script_ScaleMetricsFunc ) af_latin_metrics_scale,
                        ( AF_Script_DoneMetricsFunc ) NULL,

                        ( AF_Script_InitHintsFunc ) af_latin_hints_init,
                        ( AF_Script_ApplyHintsFunc ) af_latin_hints_apply
)


/* END */
